The present invention relates to a device in impact machines for drilling, preferably in rock, by means of a drill string comprising a set of tubes and a set of rods arranged in the set of tubes.
When drilling with a tool of the above mentioned kind the problem arises of holding the central rods in place in the surrounding tubes in a simple way so that tubes with rods can be transported at the work place without the rods falling out. According to a prior art solution a guide is mounted at one end of the tube. The rod is then inserted from the other end. Then a second guide is mounted about the other end of the rod and is locked by a lock ring.